In 1990 Humble appeared for the first time as an actress in a TV production Spymaker: The Secret Life of Ian Fleming — and was credited as "Lauren Heston .... The redhead". She was the assistant to a casting director who was looking for an actress to play a brief nude scene, and she got the job herself.[1][2]

Humble started her television career as a researcher, later transferring to presenting programmes such as Top Gear, Tomorrow's World and the 2001 series The Holiday Programme - You call the shots where the team travelled the world[3] doing whatever viewers recommended using the then-novel media of text messaging and emailing the team as they travelled.

In August 2009 Humble presented a series of programmes for the BBC in which she makes a two thousand mile journey across the Middle East, following the ancient frankincense trade route of Arabia which first connected the Arab world with the West. The series culminates in her presenting frankincense, that she has carried throughout the journey, to be used in a Christmas service at the Church of the Nativity in Bethlehem.[10]

She was recently[when?] on holiday in the northeastern region of Afghanistan where there were no signs of conflict but where the Wakhi locals were expected to be hostile. Instead, Humble found they were 'amongst the most astonishing, hospitable, warm, genuine people' she has ever met. They were also hard and tough, and Humble believes that 'if anyone thinks they are going to win a war against an Afghan they are insane!' She is writing about her experiences in Afghanistan for a forthcoming publication.[11]

From 3–7 May 2010 she appeared as the dictionary corner guest on Countdown.

In February 2011 Humble presented a three-part series of programmes, The Spice Trail, on the trail of 6 of the world's most valuable spices revealing their history, trade, mythology and usage. Part 1 - Pepper & Cinnamon, Part 2 - Nutmeg & Cloves, Part 3 - Saffron & Vanilla.[12]

Humble is married to television producerLudo Graham. They first met when she was aged 16, married in Newbury, Berkshire, in 1992, when she was 23, and in 2010 moved from Chiswick, West London, to the village of Trellech in the Wye Valley, where they have wanted to live for 'a very long time'.[15] Kate now owns her own farm after working on Lambing Live. She has a sheep called Humble, named after her, that currently lives with her friend and co-worker Adam Henson. Humble is a Naturist who "likes to get closer to nature by being naked".[16]